When replacing a distributor for any reason whether it is a malfunction or a modification, the timing must always be set back to factory or modified specifications. Timing effects how the car starts, idles and runs at various throttle settings. It also has a major impact on fuel economy as well as cylinder head temperature. Too much advance or before top dead center and the cylinder head temperature can become so high that engine damage can occur through detonation.
Tools Used: Timing light with advance ability, 9/16-inch wrench, 15mm wrench
Replace Distributor
Mark the number 1 spark plug wire location on the distributor. The number 1 plug is the first plug nearest the radiator on the driver's side. Remove the plug wires from the distributor cap on the passenger side of the engine. Remove the distributor cap and lay it next to the brake booster out of the way.
Remove the electrical connector from the distributor. Mark the position of the rotor on the base of the distributor where the cap would meet the distributor. Make a mark straight down under the nose of the rotor. It is very important to install the distributor in exactly the same position relative to the rotor. If the rotor is pointing toward the firewall it is better to mark the firewall so when the distributor is installed, the rotor is pointing toward this spot. This saves a lot of time and effort in installation in comparison to not having a reference and looking for top dead center.
Mark the base of the distributor where it contacts the block. Make a mark on the engine block and the distributor. Remove the retaining bolt at the hold down clamp at the base of the distributor. Remove any vacuum lines from the vacuum advance mechanism.
Remove the distributor by lifting and twisting slightly. Just before removing the distributor look at it and remember its orientation and where the vacuum advance is located, to ease installation.
Install the new distributor by holding it up over the hole in the block and orientate it properly so that it is in the same position it came out. The distributor shaft has a gear on the bottom side. When the distributor is inserted the gear will rotate to mesh with the cam so it will not automatically fall into place with the rotor facing your mark. Rotate the rotor clockwise about ten degrees past the mark. When it is installed you will notice that the rotor wants to rotate counter clockwise as it seats in the block. If the mark for the rotor does not line up, pull the distributor up with one hand and the other hand on the rotor. As soon as the rotor moves freely stop lifting and rotate the rotor a little farther in either direction and reinsert it until the rotor lines up with the mark.
Align the mark made on the distributor base and block. Install the distributor hold down clamp and bolt. Tighten the bolt just enough to make it difficult to turn the distributor by hand. Reconnect the electrical plug.
Install the distributor cap and the wires as marked. If you are not sure of the plug wire arrangement then the firing order is 1-8-4-3-6-5-7-2 going in a clockwise rotation. As you are standing in front of the car facing the engine, the right side or driver's side of the engine starts with number one and continues with the odd numbers (1-3-5-7) and the left or passenger side is the even number cylinders (2-4-6-8). When installing plug wires start with number one and install in a clockwise rotation.
Install the timing light. Hook the red to the positive battery terminal and black to negative. Hook the wire probe to the number one wire. Make sure all wires to the timing light are out of the way of the fan. Turn the knob on the timing light to zero degrees. If the car is carbureted block off the hole in the carburetor used for the vacuum advance. If it does not have a vacuum advance or is fuel injected remove the shorting bar plug near the distributor.
Start the car and let it warn up for two minutes. Carefully focus the light on the harmonic balancer. There will be a straight line on the balancer and an adjacent marker on the timing chain cover with a pointer. The harmonic balancer will have a set of numbers that are degrees on both sides of the straight line. The line represents top dead center. The letters BTDC mean before top dead center or advance and the letters ATDC indicate after top dead center or retard. You want the car to be idling at 4 degrees BTDC. Note where the line is in regard to the letters. Set the knob on the timing light to 4 degrees BTDC. If the line is on the retarded side rotate the distributor counter clockwise to advance the timing. If the line is on the advanced side, rotate the distributor clockwise to retard the timing. Rotate the distributor until the line lines up with the marker on the timing chain cover.
Tighten up the distributor hold down bolt and reinstall the vacuum hose to the carburetor or if fuel injected reinsert the shorting plug.
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